Let me introduce myself. My name is Mark Sisson. I’m 63 years young. I live and work in Malibu, California. In a past life I was a professional marathoner and triathlete. Now my life goal is to help 100 million people get healthy. I started this blog in 2006 to empower people to take full responsibility for their own health and enjoyment of life by investigating, discussing, and critically rethinking everything we’ve assumed to be true about health and wellness...Tell Me More
Yesterday, I explained the potential benefits and drawbacks of intermittent fasting for athletes. Maybe yesterday’s post intrigued you. Maybe you’re curious about this whole intermittent fasting thing but don’t want to sacrifice your performance in the gym or on the field.
What are my specific recommendations for athletes who wish to explore intermittent fasting? I’ve got twelve…plus some details about my own fasting and workout routine.
Athletes who want to lean out or maintain strength and performance while lowering body weight might have more success with shortened eating windows than with all day fasts or “one meal a day.” Fast for 12-16 hours, train, and break the fast. Then have 8-12 hours to eat. This will give you a nice block of almost pure fat-burning with enough of an eating window to get the calories you need to grow and maintain muscle and to recover from your training.
Having a small bit of protein (20 grams whey or maybe 10 grams BCAAs) can help if truly fasted workouts are too hard.
Whether you skip breakfast or dinner, you’ll have a block of time in the mornings before eating anything. That’s when fat-burning will be upregulated, and brisk fasted walking is a nice way to enhance it.
A heavy lifting session will get free fatty acids liberated from your adipose tissue, particularly if you’re fasted. Doing some very light cardio after your weights should in theory help you utilize all that mobilized adipose tissue. Go for a 20-minute walk, do ten minutes on the bike, or something similar.
This is a more intense version of “train low-carb, race high-carb,” a popular and well-researched method of enhancing fat adaptation and increasing fuel efficiency in endurance athletes. Training in a fasted state “forces” the athlete to burn stored fat because, well, there isn’t a whole lot of carbohydrate available. Plus, fasting necessarily increases the circulation of free fatty acids, which can be burned for fuel. This applies to everyone, not just people “racing.” The trick is to train in a fasted state (if you find it helps) and compete (whether it’s CrossFit games, a basketball game, a lifting competition, etc.) in a fed state—as long as it seems to improve your performance.
If you’re skipping dinner and eating breakfast, try morning workouts. If you’re skipping breakfast and eating lunch, try afternoon workouts.
This enhances secretion of growth hormone, which fasting already elevates. Don’t make this an every-workout habit, though. Diminishing returns and all.
This will normalize inflammation, boost growth hormone, and upregulate autophagy, giving you all the necessary co-factors for rest and recovery. Tissues will heal, joints will recover. Do nothing more on these days than easy movement (walks, hikes, bike rides, swims). Time this fast away from competition because your performance may suffer. Do these once a week or every other week.
Fifteen grams of pre-workout collagen or gelatin with a few hundred milligrams of vitamin C has been shown to improve collagen synthesis in connective tissue, and collagen shouldn’t disrupt the fast too much.
I see this a lot, especially with endurance athletes who get into intermittent fasting. They start eating breakfast later and see their times drop and their body fat disappear. They feel lighter on their feet, faster, just better all around. So they push breakfast even later and maintain the benefits, even building on them. Pretty soon they’re skipping lunch, and their performance drops off a cliff. When trying to use fasting to improve athletic performance, less is more generally speaking.
For the average couch potato to get the benefits of fasting, he or she might need to go 16 hours without food. The couch potato isn’t liberating body fat through training. The couch potato isn’t getting into ketosis through physical activity. The couch potato isn’t increasing mitochondrial density—the power plants of the cells which actually process fuel—with exercise. The athlete is doing all those things. For the athlete, many of the benefits of fasting will appear with smaller fasting windows.
“Sleeping low” is an alternative to full-on fasting that actually seems to work well. This is how you do it:
When a group of triathletes followed this protocol, both their submaximal efficiency and supramaximal capacity. High submaximal efficiency means you get more power out of each stroke/pedal/step with less energy required. Your “easy pace” becomes faster and more powerful. High supramaximal capacity means you can last longer at your maximum power output.
It’s likely that full-on fasting could be integrated into this protocol. Maybe with a compressed eating window leading up to the afternoon workout.
A few people have asked, so I’ll give an overview of how I approach this topic for myself:
Every day, I do time-restricted feeding. This isn’t a formal declaration I make with myself every day. It’s not really a schedule. It just happens naturally. I wake up and most days I’m not very hungry for anything but a cup of coffee, so I “skip” breakfast and eat my first meal around one in the afternoon following a workout.
Most of my workouts are performed in a fasted state, and I usually keep fasting after the workout for a few hours. I’ll extend that fast after the workout to really take advantage of the increased secretion of growth hormone. I’m not really trying to “get big” or anything, I’m more interested in maintaining body comp and function and increasing longevity. Natural pulses in growth hormone help with that.
Before most workouts, I’ll do some Collagen Fuel. This doesn’t seem to impair my fast and it helps me keep my joints working well—an important part of aging.
Half an hour before my weekly Ultimate Frisbee game, I’ll also include a little Primal Fuel (my whey isolate powder). This just helps me perform better. I’m not going to lose. (By the way, I’ll talk more about protein types for different functions in an upcoming post.)
That’s it for today, folks. Have you tried any of these fasting workout tips? Have they worked? Do you have any more to add? Let us know down below!
Marquet LA, Brisswalter J, Louis J, et al. Enhanced Endurance Performance by Periodization of Carbohydrate Intake: “Sleep Low” Strategy. Med Sci Sports Exerc. 2016;48(4):663-72.